# -*- encoding : utf-8 -*-
# frozen_string_literal: true

module CombinePDF
  module_function

  # Create an empty PDF object or create a PDF object from a file (parsing the file).
  # file_name:: is the name of a file to be parsed.
  def load(file_name = '', options = {})
    raise TypeError, "couldn't parse data, expecting type String" unless file_name.is_a?(String) || file_name.is_a?(Pathname)
    return PDF.new if file_name == ''
    PDF.new(PDFParser.new(IO.read(file_name, mode: 'rb').force_encoding(Encoding::ASCII_8BIT), options))
  end

  # creats a new PDF object.
  #
  # Combine PDF will check to see if `string` is a filename.
  # If it's a file name, it will attempt to load the PDF file using `CombinePDF.load`. Otherwise it will attempt parsing `string` using `CombinePDF.parse`.
  #
  # If the string is empty it will return a new PDF object (the same as parse).
  #
  # For both performance and code readability reasons, `CombinePDF.load` and `CombinePDF.parse` should be preffered unless creating a new PDF object.
  def new(string = false)
    return PDF.new unless string
    raise TypeError, "couldn't create PDF object, expecting type String" unless string.is_a?(String) || string.is_a?(Pathname)
    begin
      (begin
        File.file? string
      rescue
        false
      end) ? load(string) : parse(string)
    rescue => _e
      raise 'General PDF error - Use CombinePDF.load or CombinePDF.parse for a non-general error message (the requested file was not found OR the string received is not a valid PDF stream OR the file was found but not valid).'
    end
  end

  # Create a PDF object from a raw PDF data (parsing the data).
  # data:: is a string that represents the content of a PDF file.
  def parse(data, options = {})
    raise TypeError, "couldn't parse and data, expecting type String" unless data.is_a? String
    PDF.new(PDFParser.new(data, options))
  end

  # makes a PDFWriter object
  #
  # PDFWriter objects reresent an empty page and have the method "textbox"
  # that adds content to that page.
  #
  # PDFWriter objects are used internally for numbering pages (by creating a PDF page
  # with the page number and "stamping" it over the existing page).
  #
  # ::mediabox an Array representing the size of the PDF document. defaults to: [0.0, 0.0, 612.0, 792.0] (US Letter)
  #
  # if the page is PDFWriter object as a stamp, the final size will be that of the original page.
  def create_page(mediabox = [0, 0, 612.0, 792.0])
    PDFWriter.new mediabox
  end

  # makes a PDF object containing a table
  #
  # all the pages in this PDF object are PDFWriter objects and are
  # writable using the texbox function (should you wish to add a title, or more info)
  #
  # the main intended use of this method is to create indexes (a table of contents) for merged data.
  #
  # example:
  #   pdf = CombinePDF.create_table headers: ["header 1", "another header"], table_data: [ ["this is one row", "with two columns"] , ["this is another row", "also two columns", "the third will be ignored"] ]
  #   pdf.save "table_file.pdf"
  #
  # accepts a Hash with any of the following keys as well as any of the Page_Methods#textbox options:
  # headers:: an Array of strings with the headers (will be repeated every page).
  # table_data:: as Array of Arrays, each containing a string for each column. the first row sets the number of columns. extra columns will be ignored.
  # font:: a registered or standard font name (see Page_Methods). defaults to nil (:Helvetica).
  # header_font:: a registered or standard font name for the headers (see Page_Methods). defaults to nil (the font for all the table rows).
  # max_font_size:: the maximum font size. if the string doesn't fit, it will be resized. defaults to 14.
  # column_widths:: an array of relative column widths ([1,2] will display only the first two columns, the second twice as big as the first). defaults to nil (even widths).
  # header_color:: the header color. defaults to [0.8, 0.8, 0.8] (light gray).
  # main_color:: main row color. defaults to nil (transparent / white).
  # alternate_color:: alternate row color. defaults to [0.95, 0.95, 0.95] (very light gray).
  # font_color:: font color. defaults to [0,0,0] (black).
  # border_color:: border color. defaults to [0,0,0] (black).
  # border_width:: border width in PDF units. defaults to 1.
  # header_align:: the header text alignment within each column (:right, :left, :center). defaults to :center.
  # row_align:: the row text alignment within each column. defaults to :left (:right for RTL table).
  # direction:: the table's writing direction (:ltr or :rtl). this reffers to the direction of the columns and doesn't effect text (rtl text is automatically recognized). defaults to :ltr.
  # max_rows:: the number of rows per page, INCLUDING the header row. deafults to 25.
  # page_size:: the size of the page in PDF points. defaults to [0, 0, 595.3, 841.9] (A4).
  def create_table(options = {})
    options[:max_rows] = options[:rows_per_page] if options[:rows_per_page]

    page_size = options[:page_size] || [0, 0, 595.3, 841.9]
    table = PDF.new
    page = nil
    until options[:table_data].empty?
      page = create_page page_size
      page.write_table options
      table << page
    end
    table
  end

  def new_table(options = {})
    create_table options
  end

  # calculate a CTM value for a specific transformation.
  #
  # this could be used to apply transformation in #textbox and to convert visual
  # rotation values into actual rotation transformation.
  #
  # this method accepts a Hash containing any of the following parameters:
  #
  # deg:: the clockwise rotation to be applied, in degrees
  # tx:: the x translation to be applied.
  # ty:: the y translation to be applied.
  # sx:: the x scaling to be applied.
  # sy:: the y scaling to be applied.
  #
  # * scaling will be applied after the transformation is applied.
  #
  def calc_ctm(parameters)
    p = { deg: 0, tx: 0, ty: 0, sx: 1, sy: 1 }.merge parameters
    r = p[:deg] * Math::PI / 180
    s = Math.sin(r)
    c = Math.cos(r)
    # start with tranlation matrix
    m = Matrix[[1, 0, 0], [0, 1, 0], [p[:tx], p[:ty], 1]]
    # then rotate
    m *= Matrix[[c, s, 0], [-s, c, 0], [0, 0, 1]] if parameters[:deg]
    # then scale
    m *= Matrix[[p[:sx], 0, 0], [0, p[:sy], 0], [0, 0, 1]] if parameters[:sx] || parameters[:sy]
    # flaten array and round to 6 digits
    m.to_a.flatten.values_at(0, 1, 3, 4, 6, 7).map! { |f| f.round 6 }
  end

  # adds a correctly formatted font object to the font library.
  #
  # registered fonts will remain in the library and will only be embeded in
  # PDF objects when they are used by PDFWriter objects (for example, for numbering pages).
  #
  # this function enables plug-ins to expend the font functionality of CombinePDF.
  #
  # font_name:: a Symbol with the name of the font. if the fonts exists in the library, it will be overwritten!
  # font_metrics:: a Hash of font metrics, of the format char => {wx: char_width, boundingbox: [left_x, bottom_y, right_x, top_y]} where char == character itself (i.e. " " for space). The Hash should contain a special value :missing for the metrics of missing characters. an optional :wy might be supported in the future, for up to down fonts.
  # font_pdf_object:: a Hash in the internal format recognized by CombinePDF, that represents the font object.
  # font_cmap:: a CMap dictionary Hash) which maps unicode characters to the hex CID for the font (i.e. {"a" => "61", "z" => "7a" }).
  def register_font(font_name, font_metrics, font_pdf_object, font_cmap = nil)
    Fonts.register_font font_name, font_metrics, font_pdf_object, font_cmap
  end

  # adds an existing font (from any PDF Object) to the font library.
  #
  # returns the font on success or false on failure.
  #
  # example:
  #   fonts = CombinePDF.new("japanese_fonts.pdf").fonts(true)
  #   CombinePDF.register_font_from_pdf_object :david, fonts[0]
  #
  # VERY LIMITTED SUPPORT:
  # - at the moment it only imports Type0 fonts.
  # - also, to extract the Hash of the actual font object you were looking for, is not a trivial matter. I do it on the console.
  # font_name:: a Symbol with the name of the font registry. if the fonts exists in the library, it will be overwritten!
  # font_object:: a Hash in the internal format recognized by CombinePDF, that represents the font object.
  def register_existing_font(font_name, font_object)
    Fonts.register_font_from_pdf_object font_name, font_object
  end

  def register_font_from_pdf_object(font_name, font_object)
    register_existing_font font_name, font_object
  end

  # Gets the equality depth limit. This is the point at which CombinePDF will stop testing for nested items being equal.
  def eq_depth_limit
    @eq_depth_limit
  end
  # Sets the equality depth limit. This is the point at which CombinePDF will stop testing for nested items being equal.
  def eq_depth_limit= value
    @eq_depth_limit = value
  end
  @eq_depth_limit = 8
end